Field of the Invention
The invention relates to a method for analyzing process signals of a technical plant, in particular a power plant, having a plant process which is subdivided into functional units.
In a control center for controlling a power plant, great quantities of various measurement data which in their entirety describe the status of the plant or operation, appear constantly. The power plant operating staff has the task of identifying the particular measurement data or measurement variables that are relevant to the operating state and the task of following, analyzing and interpreting the values thereof with reference to the status of the plant. Typically, the operating staff is supported by information filters provided in the power plant control system, and those filters cause archived measurement data or variables, or those relevant solely to the current plant status, to be displayed on a screen or a gauge. The predominant amount of the total measurement data or variables ascertained is typically logged-in electronically.
A primary goal in analysis or interpretation of resultant measurement data logs, in particular in system diagnosis, is to find a cause of a report that has been generated. Particularly in troubleshooting, the operating staff must find out what error led to the appearance of a trouble signal. That requires tracing signals back, in which a chain of linked-together report events is traced back to their source from the trouble report which is received.
German Published, Non-Prosecuted Patent Application DE 44 36 658 A1, corresponding to U.S. Pat. No. 5,548,597, discloses an apparatus and a method for troubleshooting, in which correlations are made between output signals of sensors for diagnostic purposes.
In order to simplify that kind of backtracking of signals, the plant process in a power plant is typically broken down into functional units. Each of those functional units includes a small number of method steps which are logically linked to one another, analogously to a subprogram of a computer program. Each functional unit may be assigned a function plan, which represents the data flow in a functional unit, on the order of a flow chart. In order to backtrack signals, for instance in the event of an accident or a malfunction, the operating staff uses the function plans and finds the particular report chain that led to a trouble report. However, that involves major effort as well as major demands of the operating staff, who are under enormous time pressure, since fast decisions to initiate countermeasures must often be made.